1221956427 has 4 divisors (see below), whose sum is σ = 1629275240. Its totient is φ = 814637616.

The previous prime is 1221956423. The next prime is 1221956501. The reversal of 1221956427 is 7246591221.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 1221956427 - 2² = 1221956423 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221956423) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 203659402 + ... + 203659407.

It is an arithmetic number, because the mean of its divisors is an integer number (407318810).

Almost surely, 2^1221956427 is an apocalyptic number.

1221956427 is a deficient number, since it is larger than the sum of its proper divisors (407318813).

1221956427 is an equidigital number, since it uses as much as digits as its factorization.

1221956427 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 407318812.

The product of its digits is 60480, while the sum is 39.

The square root of 1221956427 is about 34956.4933453000. The cubic root of 1221956427 is about 1069.1006000797.

The spelling of 1221956427 in words is "one billion, two hundred twenty-one million, nine hundred fifty-six thousand, four hundred twenty-seven".